Lapping tool



Aug. 9, 1960 f H. w. HUNDT 2,948,089

LAPPING TOOL Filed Aug. 27, 1959 ATTORNEY-5 United States Patent ce LAPPING TOOL Herbert W. Hundt, Hasbrouck Heights, NJ. M.K.M. Machine Co., 325 Main St., Little Ferry, NJ

Filed Aug. 27, 1959, Set. No. 836,458

12 Claims. 01. s1--1s4.s

This invention relates to a lapping tool for reducing the diameter of cylindrical articles.

The invention comprehends a lapping tool having one or more lapping openings for receiving a cylindrical article therein for relative rotary movement of either the tool or article by hand or in a machine to reduce the diameter of the article,

An object of the invention is to provide a tool having one or more lapping openings for reducing the diameter of a cylindrical article by wearing away the outer surface of the article by means of an abrasive in a vehicle applied to the periphery of the article and which effects the wearing away of the outer surface thereof to the diameter required by relative movement of either the tool or article.

The invention has particular reference to a lapping tool for reducing the diameter of cylindrical articles such as metal bars, dowel pins, plug gauges, drills, reamers and the like.

A further object of the invention is to provide a lapping tool of said character in which the lapping openings may be enlarged or reduced in diameter for receiving articles varying in diameter for reducing the diameter thereof.

Still another object of the invention is to provide a tool having an arcuate periphery which may be completely annular or a fragmentary portion thereof and which is slotted to provide segmental portions on each side of a lapping opening, which segmental portions may be swung toward or away from each other by means insertable in the tool at the slotted portions for optionally reducing or enlarging the diameter of the lapping opening.

Still another object of the invention is to provide a tool of annular formation having a plurality of lapping openings for lapping cylindrical articles of different sizes and which lapping openings are substantially equally spaced and arcuately arranged and are bisected by slots extending inwardly from the periphery of the tool to thereby subdivide the outer portion of the tool into substantially equal segmental portions which are swingable for varying the sizes of the lapping openings by means inserted in the periphery of the tool at said slots.

With the foregoing and other objects in view, reference is now made to the following specification and accompanying drawings in which the preferred embodiments of the invention are illustrated.

In the drawings:

Fig. 1 is a view in elevation of a tool constructed in accordance with the invention and showing a single lapping Opening.

Fig. 2 is an edge view thereof with the adjusting screws removed.

Fig. 3 is a modified form of lapping tool provided with a plurality of lapping openings.

Fig. 4 is an edge view thereof.

Fig. 5 is still another modified form of a lapping tool provided with a plurality of lapping openings progressively increasingin size clockwise about the tool and with a plurality of lapping openings progressively in- 2,948,089 Patented Aug. 9, 1960 creasing in size counterclockwise about the tool and disposed intermediate the other openings.

Fig. 6 is a sectional view taken approximately on line 6-6 of Fig. 5.

Referring to the drawings, the lapping tool is of cylin drical or partly cylindrical formation which is slotted to form segmental portions on each-side of a lapping open ing to permit the enlargement or reduction of the size of the lapping opening so as to receive cylindrical articles which vary in size from a standard size such as 716, A or The tool is particularly adapted for lapping cylin drical articles such as metal bars, dowel pins, plug gauges, drills, reamers and the like. Thus, if a cylindrical article such as a drill or reamer has a high spot or is oversize by a few ten thousandths or the like, the segmental portions of the ,tool may be swung away from each other to provide the size of lapping opening to receive the oversized drill or reamer. The segmental portions may also be swung toward each other in order to decrease the size of the lapping opening in the event the cylindrical article is to be reduced in size below a standard size such as the fractional or decimal sizes of metal bars, dowel pins, plug gauges, drills, reamers and the like.

In the form shown in Figs. 1 and 2, the lapping tool consists of a metallic body 10 of cylidnrical formation having parallel opposite side faces 11 and 12. The lapping tool, however, may be of any formation having an arcuate peripheral portion which is provided with inwardly directed slots 13, 14 and 15 to thereby form the segmental portions 16 and 17 between the slots and on opposite sides of a lapping opening 18. The slot 14 bisects the lapping opening 18 and the several slots extend inwardly substantially the same depth to terminate in drill open ings 19, 20 and 21 respectively. Adjacent drill openings are spaced apart substantially equal distances between centers on an arc concentric with the periphery. The slots 13, 14 and 15 and the lapping opening 18 together with the drill openings 19, 20 and 21 open through the opposite side faces 11 and 12 of the body 10 with the lapping opening 18 disposed intermediate the length of the slot 14. The thickness of the body 10 between the side faces 11 and 12 is such that the segmental portions 16 and 17 may be swung or flexed toward or away from each other so as to narrow or widen the slot 14 and thereby the size and the lapping opening 18, that is the cross-sectional size thereof. Means is insertable in the slots 13, 14 and 15 for such purpose and, as illustrated, threaded openings 22, 23 and 24 are formed in the body at the outer ends of the slots respectively for receiving tapered screws 25, 26 and 27. The slots 13, 14 and 15 together with the threaded openings 22, 23 and 24 are on radii which extend centrally therethrough respectively. Thus, if the lapping opening 18 is to be reduced in size, the screw 26 will be' turned to move the same outwardly in the threaded opening 23 while the screws 25 and 27 i will be turned to tighten the same in the threaded openings 22 and 24 to thereby wedge the segmental portions 16 and 17 toward each other. For enlarging the lapping the drawings, the tool consists of a metallic body 30 of t cylindrical formation having parallel opposite side faces 31 and 32. Opening through said side faces are lapping openings 33, 34, 35, 36, 37, 38, 39 and 40 'which may vary in diameter for lapping different sizes of cylindrical articles. For instance, the lapping opening 33 may be A; of an inch in diameter and each succeeding lapping opening in clockwise direction increasing in diameter /3 of. an inch. The lapping. openings are radially arranged. with the centers thereof disposed equal distances from the center of the body and with adjacent lapping openings arcuately spaced apart equal distances between centers- .The body '36 is also provided with radially arranged slots 41 and 42 which. extend inwardly from the periphery thereof and open through the side faces 31 and 32. The slots 41 bisect the lapping openings respectively and the slots 42 are disposed medially between adjacent lapping openings. Theslots terminate at their inner ends in drill openings 43 which are arcuately spaced apart equal distancm between centers with the centers disposed equal distances from the center of the body. This provides segmental por'tions44 on opposite sides of each of the slots 41 and 42 and with the lapping openings formed inv the segmental portions disposed on opposite sides of the slots 41. Thus,.each segmental portion 44 is connected with the body 30 only by the material between the drill openings at the inner end thereof. Adjacent segmental portions may be swung toward or away from each other so as to narrow or widen the slot therebetween and thereby reduce or enlarge the size of the lapping opening formed therein. For this purpose the body 31 is provided with threaded openings 45 at the outer ends of the slots respectively for receiving tapered screws 46.

Any one of the lapping openings may be reduced in size for lapping a cylindrical article somewhat smaller in diameter than the normal size of said lapping opening by first unscrewing the screw 46 engaging in the threaded opening in the segmental portions which form the lapping opening and thereafter tightening the screws 46 at the outer ends of the slots 42 adjacent to the lapping opening whereby the segmental portions forming the lapping opening will be wedged toward each other so as to reduce the size of' the lapping opening. The lapping openings may also be enlarged in size for lapping a bar or article somewhat larger in diameter than the normal size of the lapping opening by loosening the screws 46 at the outer ends of the slots 42 adjacent to the lapping opening and thereafter tightening the screws 46 in the threaded opening in the segmental portions which form the lapping opening to thereby widen the slot between said portions and increase the size of the lapping opening.

In order to provide a lapping tool having a large number of lapping openings such as from /8 of an inch to of an inch and with lapping openings therebetween varying by A of an inch, the lapping tool may be constructed as shown in Figs. and 6 of the drawings with lapping openings 55, 56, 57, 58, 59, 60, 61 and 62 which are similar to the lapping openings 33, 34, 35, 36, 37, 38, 39 and 40 in the form shown in Figs. 3 and 4 with the lapping openings 55 being A; of an inch in diameter and each succeeding lapping opening in clockwise direction increasing of an inch. The tool may also be provided with lapping openings 63, 64, 65, 66, 67, 68, 69 and 70 with the lapping opening 63 being of an inch in diameter and each succeeding lapping opening in counterclockwise direction increasing in diameter of an inch. The said lapping openings are radially arranged similar to the lapping openings in the previous forms and each being bisected by a narrow slot 71 extending inwardly from the periphery thereof and terminating in a drill opening 72. The lapping openings open through the opposite side faces 73 and 74 of the body 75 and are radial- 1y arranged with the centers thereof disposed equal distances from the center of the body. 7 The lapping openings are arranged intermediate the length of the slots respectively with the drill openings 72 arcuately spaced apart equal distances between the centers and with the centers disposed equal distances from the center of the body. The slots thus divide the peripheral portion of the body 75 into segmental portions 77 with each lapping opening formed partly in adjacent segmental portions. As in the previous forms each segmental portion 'is connected with the body 75 only by the material between the drill openings at the inner end thereof. Any desired means may be provided for insertion in the outer ends of the slots respectively for expanding the slots so as to wedge the segmental portions on each side thereof toward the adjacent lapping openings. As illustrated, the body 75 is provided with threaded openings 78 at the outer ends of the slots respectively in. which are arranged tapered screws 79 which bridge the slots respectively.

The lapping tool may bear the normal sizes of the lapping openings respectively. As illustrated in Fig. 3 the lapping tool has the normal sizes A" and of the lapping openings 33, 3 5, 37 and 39 respectively stamped on the face 41 thereof. Also, in Fig. 5 the lapping openings 55,57, 59 and 61 have their normal sizes A3, A" and 7 respectively stamped on the side face 73. The sizes are omitted from the remaining lapping openings in Figs. 3 and 5 for the sake of clarity. The lapping openings 63 to 70 inclusive. would have their normal sizes stamped on the side face 74 in order that the sizes of each series of lapping openings may be read in clockwise direction from a side face of the tool.

The three forms shown herein have central openings 29, 47 and 80 respectively which may be employed for fastening the tools to the bed of a drill press or other machine for holding the tool in position when the article to be lapped is rotated mechanically.

While the embodiments of the invention illustrated in the drawings disclose the use of tapered screws for wedging the segmental portions to vary the size of any one of the lapping openings it is to be understood that any wedging means may be employed which is insertable in the slots for expanding the slots. The wedges may be in the form of tapered shims or the same may be tapered bars adapted to be driven into rounded openings formed particularly in adjacent sections. The tool body may be produced from steel, cast iron or alloys thereof or any equivalent material and maybe case hardened if desired after the body is drilled and slotted to provide the construction hereinbefore described. I

While the preferred forms of the invention are shown and described herein, it is to be understood that the same is not so limited but shall cover and include any and all modifications thereof which fall within the purview of the invention.

What is claimed is:

1. In a lapping tool, a metallic body having narrowly spaced opposite side faces and a lapping opening extending through said side faces, said body having a slot extending inwardly from its periphery and through said side faces and opening into said lapping opening on one side and extending beyond said lapping opening on the opposite side, said body having a slot extending through said side faces and inwardly from the periphery thereof at each side of said lapping opening to approximately the depth of said first mentioned slot to thereby provide a segment of said body at each side of said first mentioned slot which is connected with the body at its inner end, and wedging means insertable in said slots for wedging said segments for varying the width of said first mentioned slot and thereby the width between opposite portions of said lapping opening.

2. In a lapping tool, a metallic body having narrowly spaced opposite side faces and a lapping opening extending through said side faces, said body having a slot extending inwardly from its periphery and through said side faces and opening into said lapping opening on one side and extending beyond said lapping opening on the opposite side, said body having a slot extending inwardly from its periphery at each side of said lapping opening to approximately the depth of said first mentioned slot to thereby provide a segment of said body at each side of said first mentioned slot which is connected with the body at its inner end and said body having threaded openings in the periphery thereof at the outer ends ofraw said slots respectively with each opening extending partly in adjacent segments, and screws insertable in said threaded openings for wedging said segments for varying the width of said first mentioned slot and thereby the width between opposite portions of said lapping opening.

3. In a lapping tool, a metallic body of disk shaped formation having a lapping opening extending through the side faces thereof, said body having a slot extending radially inward from its periphery and through said side faces and opening into said lapping opening at one side and extending beyond said lapping opening on the opposite side, said body having a slot extending radially inward from its periphery at each side of said lapping opening to approximately the depth of said first mentioned :slot to thereby provide a segment of said body at each :side of said first mentioned slot which is connected with :said body at its inner end, and wedging means insertable :in said slots for wedging said segments for varying the width of said first mentioned slot and thereby the width Tbetween opposite portions of said lapping opening.

4. In a lapping tool, a metallic body of disk shaped .formation having a lapping opening extending through zthe side faces thereof, said body having a slot extending :through said side faces and radially inward from its periphery and opening into said lapping opening at one side :and extending beyond said lapping opening on the opposite side, said body having a slot extending through said side faces and radially inward from its periphery at each side of said lapping opening to approximately the same depth of said first mentioned slot to thereby provide a segment of said body at each side of said first mentioned slot which is connected with said body at its narrow inner end, said body having threaded openings in the periphery thereof at the outer ends of said slots respectively with each opening extending partly in adjacent segments, and screws insertable in said threaded openings for wedging said segments for varying the width of said first mentioned slot and thereby the width between opposite portions of said lapping opening.

5. -In a lapping tool, a metallic body of disk shaped formation having a plurality of radially arranged lapping openings extending axially therethrough and disposed substantially equal distances from the centers thereof to the center of said disk, said body having slots extending radially inward from its periphery and opening through the opposite sides thereof and into said lapping openings respectively at one side and extending beyond said lapping openings on the other side to thereby pro vide a segmental portion of said body at each side of each slot which is connected with said body at its narrow inner end and with each lapping opening formed partly in adjacent segmental portions, said body having openings in the periphery thereof at the outer ends of said slots respectively with each opening extending partly in adjacent segmental portions, and means insertable in said openings for wedging any adjacent pair of segmental portions to vary the width of the slot therebetween and thereby the width of lapping opening formed thereby.

6. In a lapping tool, a metallic body, of disk shaped formation having a plurality of radially arranged lapping openings extending axially therethrough and disposed substantially equal distances from the centers thereof to the center of said disk and with adjacent openings spaced substantially equal distances apart between the centers, said body having slots extending radially inward from its periphery and opening through the opposite sides thereof and into said lapping openings respectively at one side and extending beyond said lapping openings on the other side and inwardly substantially the same depth to thereby provide a segmental portion of said body at each side of each slot which is connected with said body at its narrow inner end and with each lapping opening formed partly in adjacent segmental portions, said body having threaded openings in the periphery thereof at the outer ends of said slots respectively with each opening extending partly in adjacent segmental portions, and tapered screws insertable in said threaded openings for wedging any adjacent pair of segmental portions to vary the width of the slot therebetween and thereby the width of lapping opening formed thereby.

7. In a lapping tool, a hard body having a peripheral rim and narrowly spaced opposite side faces and a lap ping opening extending through said side faces with the axis of the opening disposed in substantially right angular relation to said side faces for receiving an article for reducing the size thereof by lapping operation, said body having a slot extending inwardly from its peripheral rim and laterally through said side faces and into said lapping opening on one side thereof and said slot extending inwardly beyond said lapping opening through the side thereof opposite said one side, said body having slots extending inwardly from its peripheral rim and through said side faces with the transverse axes of said slots being disposed in substantially right angular relation with said side faces and one of said slots being arranged at each side of and in narrowly spaced relation from said first mentioned slot to approximately the depth of said first mentioned slot to thereby provide a portion of said body at each side of said first mentioned slot which is connected with said body at its inner end only and with the lapping opening formed partly in each of said portions, and said portions being adapted to be wedged apart for increasing the width between opposite parts of said lapping opening or wedged toward each other for decreasing the width between opposite parts of said lapping opening.

8. In a lapping tool, a hard body having a peripheral rim and narrowly spaced opposite side faces and a lapping opening extending through said side faces with the axis of the opening disposed in substantially right angular relation to said side faces 'for receiving an article for reducing the size thereof by lapping operation, said body having a slot extending inwardly from its peripheral rim and laterally through said side faces and into said lapping opening on one side thereof and said slot extending inwardly beyond said lapping opening through the side thereof opposite said one side, said body having slots extending inwardly from its peripheral rim and through said side faces with the transverse axes of said slots being disposed in substantially right angular relation with said 7 at each side of said first mentioned slot which is connected with said body at its inner end only and with the lapping opening formed partly in each of said portions, and said body having threaded openings extending inwardly from its rim at the outer ends of said slots respec- 3 tively with each threaded opening formed partly in said portions of the body, and tapered screws insertable in said threaded openings, one of said tapered screws being insertable in the threaded opening at the outer end of said first mentioned slot for wedging said portions of the body apart for increasing the width between opposite parts of said lapping opening, and one of said tapered screws being insertable in the threaded openings at the outer ends of said last mentioned slots for wedging said portions of the body toward each other for decreasing the width between opposite parts of said lapping opening.

9. 'In a lapping tool, a hard body having an arcuate peripheral rim and narrowly spaced opposite side faces and a lapping opening extending through said side faces with the axis of the opening disposed in substantially right angular relation to said side faces for receiving an article for reducing the size thereof by lapping operation, said body having a slot extending inwardly from its pe n'pheral rim and laterally through said side faces and into said lapping opening on one side thereof and said slot extending inwardly beyond said lapping opening through the side thereof opposite said one side, said body having slots extending inwardly from its peripheral rim and through said side faces with the transverse axes of said slots being disposed in substantially right angular relation with said side faces and one of said slots being arranged at each side of and in narrowly spaced relation from said first mentioned slot to approximately the depth of said first mentioned slot to thereby provide an inwardly tapering portion of said body at each side of said first mentioned slot which is connected with said body at its inner end only and with the lapping opening formed partly in each of said portions, and said portions being adapted to be wedged apart for increasing the width between opposite parts of said lapping opening or wedged toward each other for decreasing the width between opposite parts of said lapping opening.

10. In a lapping tool, a hard body and having an arcuate peripheral rim and narrowly spaced opposite side faces and a lapping opening extending through said side faces with the axis of the opening disposed in substantially right angular relation to said side faces for receiving an article for reducing the size thereof by lapping operation, said body having a slot extending inwardly from its peripheral rim and laterally through said side faces and into said lapping opening on one side thereof and said slot extending inwardly beyond said lapping opening through the side thereof opposite said one side, said body having slots extending inwardly from its peripheral rim and through said side faces with the transverse axes of said slots being disposed in substantially right angular relation with said side faces and one of said slots being arranged at each side of and in narrowly spaced relation from said first mentioned slot to approximately the depth of said first mentioned slot to thereby provide an inwardly tapering portion of said body at each side of said first mentioned slot which is connected with said body at its inner end only and with the lapping opening formed partly in each of said portions, and said body having threaded openings extending radially inward from its n'rn at the outer ends of said slots respectively with each threaded opening formed partly in adjacent peripheral portions, and tapered screws insertable in said threaded openings, one of said tapered screws being insertable in the threaded opening at the outer end of said first mentioned slot for wedging said tapering portions apart for increasing the width between opposite parts of said lapping opening, and one of said tapered screws being insertable in the threaded openings at the outer ends of said last mentioned slots for wedging said tapering portions toward each other for decreasing the width between opposite parts of said lapping opening.

11. In a lapping tool, a hard body having an annular peripheral rim and narrowly spaced opposite side faces, and a plurality of radially arranged lapping openings extending laterally through said body and through said side faces with the axes of the openings disposed in substantially right angular relation to said side faces and said lapping openings being disposed substantially equal distances from the centers thereof to the center of said body for receiving articles for reducing the size thereof by lapping operation, said body having slots extending inwardly from its annular rim and laterally through the side faces thereof and opening into said lapping openings respectively on one side thereof and with said slotsextend ing inwardly beyond said lapping openings through the sides thereof opposite said one side with thetransver-se axes of said slots being disposed in substantially right angular relation with said side faces to thereby provide portions of said body tapering inwardly from the rim and connected with said body at their inner ends onlyand with each of the lapping openings formed partly in adjacent tapering portions, and said portions being adapted to be wedged apart for increasing the width between opposite parts of said lapping openings or wedged toward each other for decreasing the width between opposite parts of said lapping openings respectively.

112. In a lapping tool, a'hard body having anannular peripheral rim and narrowly spaced opposite side faces, and a plurality of radially arranged lapping openings extending laterally through said body and through said side faces with the axes of the openings disposed in substantially right angular relation to said side faces and said lapping openings being disposed substantially equal distances from the centers thereof to the center of said body for receiving articles for reducing the size thereof by lapping operation, said body having slots extending inwardly from its annular rim and laterally through the side faces thereof and opening into said lapping openings respectively on one side thereof and with said slots extending inwardly beyond said lapping openings through the sides thereof opposite said one side with the transverse axes of said slots being disposed in substantially right angular relation with said side faces to thereby provide portions of said body tapering inwardly from the rim and connected with said body at their inner ends only and with each of the lapping openings formed partly in adjacent tapering portions, and said body having threaded openings extending radially inward from the periphery thereof at the outer ends of said slots respectively with each threaded opening formed partly in adjacent peripheral portions, and tapered screws insertable in said threaded openings for wedging adjacent pairs of said tapering portions apart for increasing the width between opposite parts of the lapping opening of adjacent pairs respectively or for Wedging adjacent pairs of said tapering portions toward each other for decreasing the width between opposite parts of the tapering portions of adjacent pairs respectively.

References Cited in the file of this patent UNITED STATES PATENTS 1 1,198,871 Russ Sept. 19, 1916 2,401,215 Anderson May 28, 1946 2,483,697 Giles "Oct. 4, 1949 2,787,098 Rosenhagen Apr. 2, 1957 FOREIGN PATENTS 584,385 Great Britain Jan. 14, 1947 11,059,125 France Nov. 10, 1953 

